EP3333317A1 - Railway rail guiding system - Google Patents

Abstract

Guiding system (1), comprising: a railroad rail (2) extending along an axis and comprising: an upper element (21) having a rolling face (211); a lower member (22) having a bearing face (221); a connecting element (23) between the lower and upper elements, at least one lateral recess (24) being formed between the lower and upper elements; at least first and second attitude sensors (31, 32) fixed to the rail by gluing (39) at respective positions offset along said rail axis, said attitude sensors being housed at least partially in the lateral recess; (24); a processing circuit configured to recover attitude measurements provided by the first and second attitude sensors and configured to calculate a deformation of said railroad rail (2) with respect to said axis as a function of the attitude measurements retrieved .

Description

The invention relates to the field of railway geometry and more particularly to the elongated base leveling parameter which characterizes the vertical deformation of the rail queues in the long wavelength range.

The passage of trains at high speed requires a very high precision of the geometry of the tracks. The geometry of a track has a direct impact on rail traffic. Indeed, if the parameters defining this path are outside their nominal range, the speeds of passage of the trains must be lowered for safety and comfort reasons, which can disrupt all the traffic.

Tracking the geometry of railway tracks in order to ensure their maintenance is therefore essential to ensure optimum speed of passage of trains. Any improvement in tracking the geometry of the track improves the management of traffic on the rail network and its maintenance. The tracking of the geometry of a path includes in particular the determination of the elongated base leveling signal and the determination of the elongated base dressing. Such geometric tracking is particularly important in rapidly changing areas and transition zones between an embankment and a metal structure.

A known example of tracking the geometry of railway tracks is implemented on the French rail network via a high speed train called IRIS320. This train travels through each of the high-speed lines once every 15 days. This train performs an optical and inertial measurement of the geometry of the track at each of its passages.

The operation of such a train has several disadvantages. On the one hand, some parameters of the geometry of the channels can evolve at a frequency much higher than the frequency of passage of this train. Thus, the thermal expansion of a composite steel-concrete structure, related to temperature variations, notably induces relatively fast geometric variations of the channels. If this trainset measures a geometrical variation out of standard due to a point factor, the speed of passage of high speed trains will have to be degraded while the geometry of the way is potentially satisfactory at the time of the passage of high speed trains exploited commercially. As the passage of the train IRIS320 must interfere at least with the operation of commercial trains, the geometric tracking during its passage is not necessarily representative of the geometry of the track during the passage of commercial trains. On the other hand, the Track geometry tracking is not necessarily available in real time.

Because of the cost of such a geometric tracking train and the impact that it may have on traffic, it is difficult to envisage significantly increasing the frequency of passage of such tracking trains.

• au moins deux capteurs, destinés à être disposés sur un même rail de chemin de fer, les capteurs étant destinés à être séparés l'un de l'autre par une distance mesurée le long du rail de chemin de fer,
• un circuit de traitement configuré pour récupérer des mesures fournies par les capteurs,

caractérisé en ce que les capteurs sont des capteurs d'attitude et en ce que le circuit de traitement est configuré pour calculer une déformée du rail de chemin de fer à partir des mesures récupérées.The invention aims to solve one or more of these disadvantages. The invention aims in particular to accurately calculate a global deformation of the rail at a relatively high rate, without altering the commercial traffic on the high-speed tracks. The invention thus relates to a system for detecting and measuring a deformation of a railroad rail comprising:

• at least two sensors intended to be arranged on the same railway rail, the sensors being intended to be separated from each other by a distance measured along the railroad rail,
• a processing circuit configured to retrieve measurements provided by the sensors,

characterized in that the sensors are attitude sensors and in that the processing circuit is configured to calculate a deformation of the railway rail from the retrieved measurements.

The invention then makes it possible to acquire the deformation of a rail almost in real time and whether it is in the presence or absence of a train traveling on the track. Such a detection and measurement system then makes it possible to improve the management of railway traffic by checking the geometry of the railway track in a non-invasive manner.

The invention also relates to the variants of the dependent claims. It will be understood by those skilled in the art that each of the features of the dependent variants may be independently combined with the above characteristics, without necessarily constituting an intermediate generalization.

• la déformée comprend au moins une composant en flexion et une composante en torsion dudit rail de chemin de fer.
• La déformée calculée comprend une composante en flexion, une composante en torsion et une composante en rotation dudit rail de chemin de fer.
• Chaque capteur d'attitude utilise au moins deux axes de mesure et avantageusement trois axes de mesure.
• Pour chaque capteur d'attitude, au moins l'un des axes de mesure est destiné à être colinéaire avec un axe longitudinal du rail de chemin de fer.
• Les capteurs d'attitudes sont destinés à être installés avantageusement dans des zones à évolution rapide, par exemple un appareil de dilatation ou dans des zones de transition, par exemple, entre un remblai et un ouvrage d'art.
• Un capteur d'attitude est séparé d'un capteur d'attitude adjacent par une distance mesurée le long d'un axe longitudinal du rail de chemin de fer.
• Les capteurs d'attitude sont reliés de proche en proche par une liaison filaire.
• Les capteurs d'attitude sont reliés au circuit de traitement par une liaison filaire.
• L'un au moins des capteurs d'attitude comprend un accéléromètre d'au moins deux axes de mesure configuré pour mesurer un signal continu représentatif de la déformation du rail de chemin de fer.
• L'un au moins des capteurs d'attitude comprend un accéléromètre trois axes configuré pour mesurer un signal continu représentatif de la déformation du rail de chemin de fer.

Thus the invention may include the following features, which can be taken alone or in combination:

• the deformed material comprises at least one bending component and a torsion component of said railroad rail.
• The calculated deformation comprises a bending component, a torsional component and a rotating component of said railroad rail.
• Each attitude sensor uses at least two measurement axes and advantageously three measurement axes.
• For each attitude sensor, at least one of the measurement axes is intended to be collinear with a longitudinal axis of the railroad rail.
• The attitude sensors are intended to be advantageously installed in fast-moving areas, for example an expansion device or in transition zones, for example, between an embankment and a structure.
• An attitude sensor is separated from an adjacent attitude sensor by a distance measured along a longitudinal axis of the railroad rail.
• The attitude sensors are connected one by one by a wired connection.
• The attitude sensors are connected to the processing circuit by a wired connection.
• At least one of the attitude sensors comprises an accelerometer of at least two measurement axes configured to measure a continuous signal representative of the deformation of the railroad rail.
• At least one of the attitude sensors comprises a three-axis accelerometer configured to measure a continuous signal representative of the deformation of the railroad rail.

• un rail de chemin de fer s'étendant selon un axe et comportant :
• un élément supérieur présentant une face de roulage ;
• un élément inférieur présentant une face d'appui ;
• un élément de liaison entre les éléments inférieur et supérieur, au moins un évidement latéral étant ménagé entre les éléments inférieur et supérieur sur le côté de l'élément de liaison ;

caractérisé en ce qu'il comprend en outre ;

• au moins des premier et deuxième capteurs d'attitude fixés au rail par collage en des positions respectives décalées selon ledit axe du rail, lesdits capteurs d'attitude étant logés au moins partiellement dans l'évidement latéral ;
• un circuit de traitement configuré pour récupérer des mesures d'attitude fournies par les premier et deuxième capteurs d'attitude et configuré pour calculer une déformée dudit rail de chemin de fer par rapport audit axe en fonction des mesures d'attitude récupérées.

The invention also relates to a guidance system, comprising:

• a railway rail extending along an axis and comprising:
• an upper element having a rolling face;
• a lower member having a bearing face;
• a connecting element between the lower and upper elements, at least one lateral recess being provided between the lower and upper elements on the side of the connecting element;

characterized in that it further comprises;

• at least first and second attitude sensors fixed to the rail by bonding at respective positions offset along said rail axis, said attitude sensors being housed at least partially in the lateral recess;
• a processing circuit configured to retrieve attitude measurements provided by the first and second attitude sensors and configured to calculate a deformation of said rail rail relative to said axis based on the retrieved attitude measurements.

• chaque capteur d'attitude comprend un accéléromètre configuré pour mesurer un signal continu représentatif de la déformation du rail de chemin de fer.
• Lesdits premiers et deuxièmes capteurs d'attitude comportent chacun :
  • un support en matériau isolant électrique collé au rail ; et
  • un boîtier fixé au support.
• Lesdits premiers et deuxièmes capteurs d'attitude comportent chacun un boîtier formant une cage de Faraday.
• Le support comporte deux faces épousant la forme de faces respectives de l'élément inférieur et de l'élément de liaison.
• Chacun desdits premier et deuxième capteurs d'attitude comprend :
  • un accéléromètre configuré pour mesurer une composante d'accélération selon ledit axe ;
  • un circuit de calcul configuré pour calculer l'attitude du capteur d'attitude en fonction de la mesure de l'accéléromètre.
• Ledit accéléromètre respectif des premier et deuxième capteurs d'attitude est un accéléromètre à 3 axes de mesure non colinéaires.
• Lesdits premiers et deuxièmes capteurs d'attitude sont collés à l'élément de liaison et à l'élément inférieur.
• Lesdits premier et deuxième capteurs d'attitude sont distants d'une distance au plus égale à 5 mètres selon l'axe du rail.
• Le système de guidage comprend en outre une connexion filaire entre les premier et deuxième capteurs d'attitude, ladite connexion filaire étant fixée à l'élément inférieur du rail par l'intermédiaire d'une agrafe.
• Un espace est ménagé dans l'évidement latéral entre une face supérieure des capteurs d'attitude et l'élément supérieur.

According to one or more variants, the invention may comprise the characteristics listed above as well as the following, these characteristics being able to be taken alone or in combination:

• each attitude sensor comprises an accelerometer configured to measure a continuous signal representative of the deformation of the railroad rail.
• Said first and second attitude sensors each comprise:
  • a support of electrical insulating material glued to the rail; and
  • a housing attached to the support.
• Said first and second attitude sensors each comprise a casing forming a Faraday cage.
• The support comprises two faces matching the shape of respective faces of the lower element and the connecting element.
• Each of said first and second attitude sensors comprises:
  • an accelerometer configured to measure an acceleration component along said axis;
  • a calculation circuit configured to calculate the attitude of the attitude sensor according to the measurement of the accelerometer.
• Said respective accelerometer of the first and second attitude sensors is an accelerometer with 3 non-collinear measuring axes.
• Said first and second attitude sensors are glued to the connecting element and to the lower element.
• Said first and second attitude sensors are spaced at a distance of at most 5 meters along the axis of the rail.
• The guidance system further comprises a wire connection between the first and second attitude sensors, said wire connection being attached to the lower member of the rail via a staple.
• A space is provided in the lateral recess between an upper face of the attitude sensors and the upper element.

• la figure 1 est une vue en coupe transversale schématique d'un exemple de rail de chemin de fer ;
• la figure 2 est une vue de côté d'un exemple de système de guidage selon un exemple de mode de réalisation de l'invention, incluant un rail de chemin de fer et un dispositif de détermination d'attitude du rail dénommé capteur d'attitude;
• la figure 3 est une vue en coupe transversale du système au niveau d'un capteur d'attitude fixé au rail ;
• la figure 4 est une vue en coupe transversale du système au niveau d'un câble de connexion entre des capteurs d'attitude;
• les figures 5 et 6 sont des vues en coupe transversale d'un exemple de capteur d'attitude ;
• la figure 7 est une vue de dessus d'un exemple de configuration au niveau d'un appareil de dilatation ; et
• la figure 8 est une représentation schématique d'une déformation verticale d'un rail de chemin de fer.

Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

• the figure 1 is a schematic cross-sectional view of an example of a railroad rail;
• the figure 2 is a side view of an exemplary guidance system according to an exemplary embodiment of the invention, including a railroad rail and a rail attitude determining device referred to as an attitude sensor;
• the figure 3 is a cross-sectional view of the system at an attitude sensor attached to the rail;
• the figure 4 is a cross-sectional view of the system at a connection cable between attitude sensors;
• the Figures 5 and 6 are cross-sectional views of an example of an attitude sensor;
• the figure 7 is a top view of an exemplary configuration at a dilation apparatus; and
• the figure 8 is a schematic representation of a vertical deformation of a railroad rail.

• une immunité aux conditions météorologiques extérieures ;
• une immunité aux courants élevés traversant les rails ;
• une immunité aux perturbations électromagnétiques importantes lors du passage d'un train ;
• l'absence d'altération de l'intégrité structurelle du rail ;
• la résistance au passage d'un train et/ou au passage d'une rame de maintenance de la voie ;
• ne pas constituer un obstacle au passage d'un train et/ou au passage d'une rame de maintenance de la voie.

The determination of the deformation of a rail according to the invention satisfies a certain number of constraints:

• immunity to external weather conditions;
• immunity to high currents crossing the rails;
• immunity to significant electromagnetic disturbances during the passage of a train;
• the lack of alteration of the structural integrity of the rail;
• resistance to the passage of a train and / or the passage of a maintenance train of the track;
• do not constitute an obstacle to the passage of a train and / or the passage of a maintenance train of the track.

The figure 1 is a schematic cross-sectional view of an example of rail guide rail 2. Such a rail 2 is made of steel and is elongated along an axis, in a manner known per se. Such a rail 2 typically has an extrusion shape or has a very high radius of curvature. The rail 2 is here decomposed into three distinct parts for the sake of comprehension, these three parts being illustrated by elements separated by discontinuous lines at the figure 1 .

• un élément supérieur 21 (généralement désigné par le terme champignon), présentant une face supérieure 211 destinée au roulage, sensiblement plate ;
• un élément inférieur 22 (généralement désigné par le terme patin), présentant une face inférieure 221. La face inférieure 221 est destinée à servir de face d'appui et/ou de fixation sur un support non illustré, tel qu'une traverse, l'élément inférieur 22 comporte également des faces supérieures 222, orientées vers l'élément supérieur 21 ;
• un élément de liaison 23 (généralement désigné par le terme âme), reliant l'élément supérieur 21 à l'élément inférieur 22. La largeur du rail de guidage 2 est réduite au niveau de l'élément de liaison 23. L'élément de liaison 23 comporte des faces 231 sensiblement verticales. Au moins un évidement latéral 24 est ménagé entre l'élément supérieur 21 et l'élément inférieur 22, sur le côté de l'élément de liaison 23. Dans l'exemple illustré, le rail de guidage 2 est sensiblement symétrique et comporte des évidements latéraux 24 entre les éléments 21 et 22, de part et d'autre d'un axe vertical passant par l'élément de liaison 23. Le rail de guidage 2 présente ainsi une section transversale ayant globalement la forme d'un I ou la forme de deux C accolés tête-bêche. Un exemple de rail est notamment normalisé sous la référence 60E1. Un rail 2 présente typiquement une longueur de plusieurs dizaines de mètres, par exemple de 100 mètres.

The guide rail 2 comprises:

• an upper member 21 (generally referred to as the mushroom), having an upper surface 211 for rolling, substantially flat;
• a lower member 22 (generally designated by the term pad), having a lower face 221. The lower face 221 is intended to serve as a bearing face and / or attachment to a non-illustrated support, such as a cross member, lower element 22 also has upper faces 222, oriented towards the upper element 21;
• a connecting element 23 (generally referred to as the core), connecting the upper element 21 to the lower element 22. The width of the guide rail 2 is reduced at the level of the connecting element 23. The element of link 23 has faces 231 substantially vertical. At least one lateral recess 24 is formed between the upper element 21 and the lower element 22, on the side of the connecting element 23. In the example shown, the guide rail 2 is substantially symmetrical and has lateral recesses 24 between the elements 21 and 22, on either side of a vertical axis passing through the connecting member 23. The guide rail 2 thus has a cross section having generally the shape of a I or the form of two C contiguous head to tail. An example of a rail is in particular standardized under the reference 60E1. A rail 2 typically has a length of several tens of meters, for example 100 meters.

The figure 2 is a side view of an exemplary guide system 1 including a rail 2 is a rail attitude determining device. The attitude determination device here comprises in particular two attitude sensors 31 and 32, fixed to the rail 2 and offset along the longitudinal axis of the rail 2.

). Une telle calibration de chacun des capteurs d'attitude 31, 32 permet alors de s'affranchir des problèmes d'alignement des capteurs d'attitude 31, 32 lors de leur installation sur le rail 2.In other words, the two attitude sensors 31, 32 are separated from each other by a distance D measured along the longitudinal axis of the rail 2 (cf. figure 8 ). It should be noted that an attitude sensor 31, 32 may correspond to a sensor using at least two measurement axes. Preferably, an attitude sensor uses three measurement axes, with the measurement on the third axis to ensure proper calibration. An adequate calibration is that for which the norm N of the three axes is equal to 1 (N = 1 $=\sqrt{x^2+{\mathrm{there}}^2+z^2}$

). Such a calibration of each of the attitude sensors 31, 32 then makes it possible to overcome the problems of alignment of the attitude sensors 31, 32 during their installation on the rail 2.

The attitude sensors 31 and 32 are housed at least partially in a lateral recess 24 of the rail 2. Thus, the lateral dimensions of the attitude sensors 31 and 32 are limited, which reduces the risk of contact with Advantageously, the attitude sensors 31 and 32 are positioned in the lateral recess 24 oriented towards the median zone defined between the two rails forming a channel, the lateral recess 24 being usually designated as the inner face of the rail. rail.

A processing circuit 4 is configured to recover the attitude measurements provided by the attitude sensors 31 and 32. The processing circuit 4 is configured to calculate a deformation of the rail 2 relative to its longitudinal axis. The processing circuit 4 is here offset with respect to the rail 2. The processing circuit 4 is for example implemented in the form of software running on a computer. The processing circuit 4 is here connected to the attitude sensor 32 via a wired connection 41, comprising a supply wiring and a communication wiring. The attitude sensors, here in particular the attitude sensors 31 and 32, are connected from close via wired link 40, including including power wiring and communication wiring.

More specifically, in the case of a larger plurality of attitude sensors 31, 32, for example 10 in number, each attitude sensor is connected by wire connection 40 to the next attitude sensor, that is, that is, at least one of the directly adjacent attitude sensors.

The figure 3 is a cross-sectional view of the guidance system 1 at an attitude sensor 30 attached to the rail 2. The attitude sensor 30 is fixed to the rail 2 by means of a glue film 39. to optimize the mechanical connection between the attitude sensor 30 and the rail 2, the glue film 39 connects the attitude sensor 30 to both an upper face 222 of the lower element 22, and a vertical face 231 of the connecting element 23.

Advantageously, the attitude sensor 30 comprises two faces respectively conforming to the shape of the upper face 222 and the shape of the vertical face 231, in order to favor its positioning with respect to the rail 2 and the mechanical strength of the adhesive film 39.

The fixing of the attitude sensors 30 by an adhesive film 39 makes it possible not to alter the structural integrity of the rail and makes it possible to guarantee an excellent positioning of each attitude sensor 30 with respect to the rail 2, in spite of the mechanical stresses related thereto. when passing trains or maintenance trains. Such an attachment makes it possible not to introduce uncertainties that could be related to a relative movement between an attitude sensor 30 and the rail 2.

Preferably, the adhesive film 39 is applied so as to form a continuous layer between the attitude sensor 30 and the rail 2, in order to prevent any moisture infiltration between the sensor 30, 31, 32 and the rail 2 , which could cause a degradation of the rail 2 and distort the measurements acquired by the attitude sensor 30, 31 or 32.

By a suitable choice of glue film 39, the mechanical stiffness and the dielectric permittivity between the rail 2 and the inside of the housing 320 (detailed below) can be increased by choosing an electrically insulating adhesive.

The adhesive film 39 may for example be made with an epoxy adhesive sold under the reference Loctite EA 9466 by Henkel, or an epoxy adhesive marketed under the reference DP8405NS by the company 3M. Such a glue is for example chosen for its mechanical strength properties in peeling, peeling and shearing, electrical insulation, resistance to a large number of chemicals, resistance in time and vibration resistance. Tearing and holding tests Temperature have demonstrated the satisfactory properties of the selected glue films 39. The adhesive film 39 is advantageously applied after grinding and degreasing of the surfaces 231 and 222.

Furthermore, a space 240 is formed in a lateral recess 24, between an upper face of the attitude sensor 30 and the upper element 21. This space is intended to allow the passage of maintenance equipment rails (for example a stuffing frame) pinching the upper element 21, without risk of altering the attitude sensor 30.

The figure 4 is a cross-sectional view of the system 1 at an attachment of a wire connection 40 to the rail 2. The wire connection 40 extends along an upper face 222 between two adjacent attitude sensors. The wired connection 40 is advantageously fixed to the lower element 22 by means of a clip 42 secured to the lower element 22. In order to have an optimal precision on the determination of the deformation of the rail, the sensors of FIG. adjacent attitudes are advantageously distant from a distance D of at most 5 meters, preferably at most 3 meters.

Advantageously, in rapidly changing areas, for example in a dilatation apparatus, and transition zones, for example between an embankment and a structure, an attitude sensor 30, 31 or 32 is arranged between each cross member. of the rail 2, the cross member being the part joining two parallel rails 2 forming the railway. Thus the distance D separating two attitude sensors 30, 31, 32 directly adjacent along the same rail 2, is substantially equal to 55 centimeters. By substantially, it is understood an uncertainty of plus or minus 10%. The typical distance D can be modified if the standard spacing between adjacent sleepers is different, for example when it depends on the installation areas or the use of the railway.

The Figures 5 and 6 are sectional views of an exemplary attitude sensor structure 30 at two axially distinct locations. The attitude sensor 30 comprises a support 310 intended to be fixed to the rail 2 by gluing. The support 310 thus has a face 311 intended to fit a vertical face 231 of the connecting element 23, and a face 312 intended to fit an upper face 222 of the lower element 22. The support 310 is formed of material electrically insulating, for example PTFE. The support 310 thus makes it possible to make the attitude sensor 30 immune to the current loops passing through the rail 2 during the passage of a catenary feed train. Indeed, this makes it possible to avoid disturbing the measurements acquired by the attitude sensors 30, 31, 32 and makes it possible to avoid damaging the attitude sensors whether they are in the measuring phase or in the rest phase.

The attitude sensor 30 further comprises a housing 320. The housing 320 comprises a shell 321 and a cover 322 delimiting a housing 323. The housing 323 is insulated from the weather in order to take measurements in difficult climatic conditions, including variations temperature, presence of moisture, wind and dust, or rain or snow. The housing 320 is fixed to the support 310 by any appropriate means, for example by gluing. The housing 320 is advantageously configured to form a Faraday cage around the housing 323. The housing 323 is thus preserved strong electromagnetic disturbances from power sources or energy transport during the passage of a train. The housing 320 (in particular its shell 321 and its cover 322) may for example be formed of a plastic (for example PA) charged with metal particles, or coated with metal walls for example obtained by electroplating. Advantageously, the housing 320 is formed of metal.

The attitude sensor 30, 31, 32 comprises an electronic circuit 342 provided with processing means, and an accelerometer 341 fixed for example on the substrate of the electronic circuit 342. The electronic circuit 342 and the accelerometer 341 are housed at the Inside the housing 323. The electronic circuit 342 and / or the accelerometer 341 can be embedded in a resin in order to improve their resistance to external aggression. The coating material is, for example, polyurethane or epoxy, which protects against chemical and physico-chemical aggressions, which favors the absorption of possible shocks and stresses. The electronic circuit 342 can be fixed by gluing to the housing 320.

On the sectional view of the figure 5 , the support 310 has a solid shape supporting the housing 320. In the sectional view of the figure 6 , the support 310 is illustrated at a recess 325 for passing the wire connection 40. The housing 320 has two openings at a lower face. These openings open on the recess 325 and are crossed by wire connections 40. The wired connections 40 have the role of providing power to the electronic circuit 342 and the accelerometer 341, as well as to ensure communication with the attitude sensors 30, 31, 32 adjacent. The use of wired connections 40 makes it possible to improve the immunity of communications to electromagnetic disturbances. In addition, the advantage of using the wired connections 40 over a wireless connection is that the measurements made by the attitude sensors 30, 31, 32 at a given moment are better synchronized.

The electronic circuits 342 may be configured to provide feed repetition to an adjacent attitude sensor 30, 31, 32.

The openings of the housing 320 are sealed by means of cable glands 324. Advantageously, these glands 324 include a shielding recovery so as not to alter a Faraday cage formed by the housing 320.

Each attitude sensor 30, 31, 32 will advantageously comprise an accelerometer 341 with three axes. Preferably, the accelerometer is of mass-spring or capacitive type. Advantageously, the accelerometer is configured to measure a continuous signal representative of the deformation of the rail 2.

The accelerometer 341 may for example be the accelerometer marketed by Safran under the reference MS9001. Each attitude sensor 30 may also further comprise a temperature sensor and / or a multi-axis magnetometer.

The guidance system 1 may for example be used to determine elongated base leveling. The elongated base leveling corresponds to a spatially filtered version of the average leveling defined as the average of the leveling of each rail line of the studied track. The leveling of a rail queue corresponds to the vertical deformation of this line. Consequently, the instrumentation of the two rows of rails that make up a track by a system that measures the vertical deformation of these lines allows an estimation of the elongated base leveling.

• l'inclinaison du capteur d'attitude 30 correspond alors à l'angle du rail 2 au point de mesure par rapport à un axe longitudinal d'un référentiel fixe ;
• le roulis correspond à l'angle de la rotation autour de l'axe dirigé par la tangente au rail 2 ;
• le lacet correspond à l'angle de la rotation autour d'un axe vertical.

The guidance system 1 comprises a plurality of attitude sensors 30 spaced apart from each other in the longitudinal direction of the rail 2. The attitude of a sensor is defined by the rotation which makes it possible to pass from the axis system of the sensor to a reference axis system. The attitude can be set by three angles: tilt, roll and yaw. There are several ways to define these three angles. When an attitude sensor 30 is fixed to the rail 2 so that one of its axes is parallel to the longitudinal axis of the rail 2, then:

• the inclination of the attitude sensor 30 then corresponds to the angle of the rail 2 at the measurement point with respect to a longitudinal axis of a fixed reference frame;
• the roll corresponds to the angle of rotation about the axis directed by the tangent to the rail 2;
• the lace corresponds to the angle of rotation around a vertical axis.

The system 1 here comprises in particular attitude sensors (in particular 31 and 32) distributed along the length of the rail 2. The attitude sensors 31 and 32 are fixed to the rail 2, which makes it possible to link their attitude to the deformation of the 1. Instrumentation with attitude sensors 31 and 32 according to the invention is typically intended to detect a deformation of 1 mm over 10 meters in length of the rail 2, along the x, y and z axes (cf. figure 4 ).

The attitude sensors 31 to 32 each comprise, for example, an accelerometer configured to measure at least one acceleration component along the longitudinal axis of the rail 2, and an electronic circuit 342 configured to calculate the attitude of the sensor as a function of the measuring its accelerometer 341, in a manner known per se.

The accelerometers 341 of the attitude sensors 31 and 32 are for example formed of MEMS components. Such MEMS sensors have demonstrated temperature and time stability, and can currently exhibit acceleration resolutions better than 0.1 10 ^-3 g.

As detailed below, the processing circuit 4 retrieves the attitude measurements provided (for example the raw measurement data of the attitude sensors) by each attitude sensor 31 and 32 and calculates a deformation of the rail 2 according to of these attitude measures.

More precisely, it is the network organization of the different attitude sensors 30, 31, 32 which makes it possible to measure the deformation. Indeed, as will be described in relation to the figure 8 , an attitude sensor 30, 31, 32 located at the critical point of the deformation of the rail 2 will not necessarily raise by itself the deformation of the rail 2. On the other hand, the adjacent attitude sensors 30, 31, 32 will measure the displacement of their axes relative to their initial state. It should be noted that the initial state of the attitude sensors 30, 31, 32 is programmed during their calibration, the calibration being advantageously performed on the day of their installation on the rail 2. Preferably, the installation of the sensors attitude 30, 31, 32 is on rails 2 out of the factory.

The processing circuit 4 is configured to recover the attitude measurements of the various attitude sensors 31 and 32 in particular. The processing circuit 4 is configured to calculate the overall deformation or the curvature of the rail 2, according to the different attitude measurements retrieved. The processing circuit 4 can perform a temporal filtering of the raw data provided by the attitude sensors 30, 31, 32, to improve the signal-to-noise ratio. Such temporal filtering is justified by the assumption that a rail queue is static over a window of a few minutes. For example, a sampling frequency of 1 Hz may be considered.

During the deformation of the rail 2 in flexion or in torsion, the attitude of the different attitude sensors is modified, because of their mechanical coupling with the rail 2. The processing circuit 4 is programmed to evaluate the attitude in all point of the rail 2, from the measurements provided by the attitude sensors. Such an evaluation is for example carried out by means of interpolation methods, such as cubic spline interpolation. Examples of interpolation and reconstruction methods are described, for example, in Chapter 1 of the doctoral thesis of N. Sprynski, "Reconstruction of curves and surfaces from tangential data", Joseph Fourier University, Grenoble, France, 2007 .

Similarly, during the deformation of the rail 2 in torsion, the attitude of the various sensors is modified, because of their mechanical coupling to the rail 2.

An example for calculating the deformation of the rail 2 from the attitude / inclination measurements of the different attitude sensors can be as follows. It is assumed that the attitude sensors are 3-axis sensors, making a measurement m (t, s) expressed in g, with t the measurement instant and s the curvilinear abscissa of a sensor along the rail 2. With φ (t, s) the inclination and η (t, s) its roll introduced above: $$m\left(t,s\right)=\left[\begin{array}{c}\cos \left(\mathrm{\phi }\left(\mathrm{t},\mathrm{s}\right)\right)\\ -\sin \left(\mathrm{\phi }\left(\mathrm{t},\mathrm{s}\right)\right)*\sin \left(\mathrm{\eta }\left(\mathrm{t},\mathrm{s}\right)\right)\\ -\sin \left(\mathrm{\phi }\left(\mathrm{t},\mathrm{s}\right)\right)*\cos \left(\mathrm{\eta }\left(\mathrm{t},\mathrm{s}\right)\right)\end{array}\right]$$

The 3-axis accelerometer attitude sensors in the rail 2, provide a spatial sampling of the full length inclination / attitude provided with these sensors, as a function of the curvilinear abscissa along this rail 2. Using a model of interpolation or approximation from the discrete attitudes provided by the attitude sensors attached to the rail 2, it is possible to extrapolate a continuous function representative of the inclination / attitude as a function of the curvilinear abscissa along the rail 2. The vertical deformation of rail 2 at all points is defined using this function in the following relation: $$\mathit{def}\left(t,s\right)=\left[\begin{array}{c}x\left(t,s\right)\\ \mathrm{there}\left(t,s\right)\end{array}\right]=\mathit{def}\left(t,s0\right)+{\int }_{u=s0}^s\left[\begin{array}{c}\cos \left(\mathrm{\phi }\left(\mathrm{t},\mathrm{u}\right)\right)\\ \sin \left(\mathrm{\phi }\left(\mathrm{t},\mathrm{u}\right)\right)\end{array}\right]du$$

$\stackrel{\rightharpoonup }{y},$

) où y est colinéaire à la gravité et $\stackrel{\rightharpoonup }{x}$

est tel que le plan (O, x, y) contient la courbe représentative du rail.In the reference (O, $\stackrel{\rightharpoonup }{x},$

$\stackrel{\rightharpoonup }{\mathrm{there}},$

where it is collinear with gravity and $\stackrel{\rightharpoonup }{x}$

is such that the plane (O, x, y) contains the representative curve of the rail.

Assuming that the curvilinear abscissa point s0 remains fixed in time, then Def (t, s0) = 0. The overall deformation is then completely determined by means of the continuous inclination function.

In the case where the attitude sensor 30, 31, 32 comprises a magnetometer, it is then possible to measure the lateral displacement of the rail 2, that is to say a rotation about the vertical axis called yaw. However, given the presence of the housing 320 possibly forming a cage of Faraday, it is necessary to ensure that it is permeable to the magnetic field and impervious to the electric field.

Thus, it is understood that according to the invention, the attitude sensors 30, 31, 32 make it possible to detect and measure torsional and flexural deformations, using triaxial accelerometers and, alternatively, realization, these attitude sensors 30, 31, 32 are also capable of detecting and measuring rotational deformations when equipped with magnetometers.

• la technologie du capteur d'attitude 30, 31, 32, influe sur les paramètres suivants : sa résolution (plus petite variation d'accélération qui puisse être détectée), son écart-type de bruit de mesure (lié à la résolution dans certaines technologies), sa stabilité en température (dérive en mg/°K) et sa stabilité dans le temps (dérive en mg/an). La notion de stabilité dans le temps intègre les dérives de sensibilité et de calibrage du capteur d'attitude mais également les dérives des angles entre chaque axe de mesure pour un accéléromètre à 3 axes lorsqu'il est composé de 3 accéléromètres monoaxes perpendiculaires ;
• la densité et la répartition spatiale des capteurs d'attitude le long du rail 2. La reconstruction est d'autant plus précise que le nombre de noeuds de mesure est élevé et que leur répartition est adéquate (cf. figure 8). Pour un rail 2 de structure géométrique sensiblement homogène sur sa longueur, une répartition des capteurs d'attitude uniforme selon son axe longitudinal est optimale. Pour une telle structure, avec les capteurs d'attitude testés, une quantité de 3 capteurs d'attitude par 10 mètres de longueur de rail s'avère suffisante, et un capteur d'attitude tous les mètres est optimal. Il est à noter que pour les zones à évolution rapide et les zones de transition entre un remblai et un ouvrage d'art métallique, un capteur tous les 55 centimètres est optimal ou espacé d'une distance comparable au pas de répétition des traverses à 10% près ;
• les incertitudes sur le montage des capteurs d'attitude 30, 31, 32. Un accéléromètre 3 axes permet d'estimer l'inclinaison que son propre repère forme avec la direction d'orientation du rail 2. La déformée globale calculée est d'autant plus précise que l'axe du repère qui définit l'inclinaison de chaque accéléromètre d'un capteur d'attitude est tangent à la déformée globale à calculer ;
• les incertitudes sur les abscisses curvilignes des capteurs d'attitude 30, 31, 32. L'incertitude sur l'abscisse d'un capteur d'attitude 30, 31, 32 influe sur la performance de reconstruction ;
• le modèle d'interpolation/d'approximation de la fonction continue d'inclinaison/attitude. Pour un rail 2 dont la fibre neutre est sensiblement rectiligne, la fonction d'inclinaison est lisse et peut être approximée par l'intermédiaire d'une spline cubique. D'autres modèles d'interpolation sont connus en soi de l'homme du métier pour définir une fonction d'inclinaison à partir de mesures ponctuelles.

The accuracy of the calculation of the overall deformation of the rail 2 depends in particular on the following parameters of the attitude sensor 30, 31, 32:

• the attitude sensor technology 30, 31, 32 influences the following parameters: its resolution (the smallest variation of acceleration that can be detected), its standard deviation of measurement noise (related to the resolution in certain technologies ), its temperature stability (drift in mg / ° K) and its stability over time (drift in mg / year). The notion of stability in time integrates the drifts of sensitivity and calibration of the attitude sensor but also the drifts of the angles between each axis of measurement for a 3-axis accelerometer when it is composed of 3 perpendicular mono-axis accelerometers;
• the density and the spatial distribution of the attitude sensors along the rail 2. The reconstruction is more accurate as the number of measurement nodes is high and their distribution is adequate (cf. figure 8 ). For a rail 2 of geometric structure substantially homogeneous over its length, a distribution of uniform attitude sensors along its longitudinal axis is optimal. For such a structure, with the attitude sensors tested, a quantity of 3 attitude sensors per 10 meters of rail length is sufficient, and an attitude sensor every meter is optimal. It should be noted that for fast moving areas and transition zones between an embankment and a metal structure, a sensor every 55 centimeters is optimal or spaced at a distance comparable to the repetition pitch of 10-foot sleepers. % near ;
• the uncertainties on the mounting of the attitude sensors 30, 31, 32. A 3-axis accelerometer makes it possible to estimate the inclination that its own mark forms with the orientation direction of the rail 2. The calculated overall deformation is all the greater more accurate than the axis of the marker which defines the inclination of each accelerometer of an attitude sensor is tangent to the overall deformation to calculate;
• the uncertainties on the curvilinear abscissa of the attitude sensors 30, 31, 32. The uncertainty on the abscissa of an attitude sensor 30, 31, 32 influences the reconstruction performance;
• the model of interpolation / approximation of the continuous function of inclination / attitude. For a rail 2 whose neutral fiber is substantially rectilinear, the tilting function is smooth and can be approximated via a cubic spline. Other interpolation models are known per se to those skilled in the art for defining a tilt function from point measurements.

With a guide system 1 according to the invention, the geometry of the rail 2 can be followed at a relatively high frequency, for example every 15 minutes, even every 1 minute, without affecting the movement of trains on the tracks. With such a temporal frequency or rate, it is possible in particular to limit to the strict minimum the period during which the train speed is reduced because the elongated base leveling exceeds a certain threshold.

It is possible to implement a calibration step of the system 1. For this purpose, it is possible, for example, to traverse the rail 2 by a mobile reference attitude sensor. The measurements of this reference attitude sensor make it possible, for example, to align the mark of each attitude sensor fixed to the rail 2, as a function of the measurements made by the mobile attitude sensor. The calibration may also include the precise location of the various attitude sensors 30 along the longitudinal axis of the rail 2.

The invention is particularly advantageous for a transition zone between an embankment and a structure, particularly subject to mechanical stresses.

The figure 7 further illustrates in schematic top view a particular application to a half dilating apparatus at one end of a transition zone. The half-expansion device comprises two parallel rails 201 and 202. Only the attitude sensors 301 to 303 of the rail 201 have been illustrated. The rails 201 and 202 are fixed to crosspieces by means of stirrups 25. These stirrups 25 interfere with the passage of the wire connections 40. Consequently, part of the wire connections 40 is offset towards the median zone between the rails 201 and 202, at each stirrup 25.

The figure 8 schematically illustrates a deformation undergone by a rail 2 in a rapidly changing area, with an initial state represented by a dashed line and a deformed state represented in full line. The initial state is at ground level, while the deformed state is below ground level. Attitude sensors 30 were placed every fifty centimeters (D) along rail 2 in this fast moving area. In order to better understand the importance of the network use of the attitude sensors 30, one of their axes has been represented.

In this particular case, the attitude sensor 30 located at the critical point of the vertical deformation of the rail 2, called a critical attitude sensor 35 will not detect and measure deformation, since the orientation of its axes remains unchanged from the initial state. In contrast, the adjacent attitude sensors 30 have at least one of their axes oriented differently from the initial state, which will allow them to quantitatively measure the deformation experienced by the rail 2. Once these data recovered by the processing circuit 4, the calculation of the deformed on this rapidly changing area is achieved.

Claims (15)

A system for detecting and measuring a deformation of a railroad rail (2) comprising: at least two sensors (30, 31, 32, 35) intended to be arranged on the same railroad rail (2), the sensors (30, 31, 32, 35) being intended to be separated from each other; on the other by a distance (D) measured along the railroad rail (2), a processing circuit (4) configured to recover measurements provided by the sensors (30, 31, 32, 35), characterized in that the sensors are attitude sensors (30, 31, 32, 35) and in that the processing circuit (4) is configured to calculate a deformation of the railroad rail (2) from the measures recovered. A detection and measurement system according to claim 1, characterized in that the calculated deformation comprises at least one bending component and a torsional component of said railroad rail (2). Sensing and measuring system according to Claim 1 or 2, characterized in that each attitude sensor (30, 31, 32, 35) uses three measuring axes. Sensing and measuring system according to one of Claims 1 to 3, characterized in that at least one of the attitude sensors (30, 31, 32, 35) comprises an accelerometer of at least two axes configured for measuring a continuous signal representative of the deformation of the railroad rail (2). Guiding system (1), comprising: a railroad rail (2) extending along an axis and comprising: - an upper member (21) having a rolling face (211); - a lower member (22) having a bearing face (221); - a connecting element (23) between the lower and upper elements, at least one lateral recess (24) being formed between the lower and upper elements on the side of the connecting element; characterized in that it further comprises; at least first and second attitude sensors (31, 32) fixed to the rail by gluing (39) at respective positions offset along said rail axis, said attitude sensors being housed at least partially in the lateral recess; (24); a processing circuit (4) configured to recover attitude measurements from the first and second attitude sensors (31,32) and configured to calculate a deformation of said railroad rail (2) with respect to said axis according to the attitude measurements retrieved. The guidance system (1) of claim 5, wherein each attitude sensor (30, 31, 32) comprises an accelerometer configured to measure a continuous signal representative of the deformation of the railroad rail. The guidance system (1) according to claim 5 or 6, wherein said first and second attitude sensors (31, 32) each comprise: - a support (310) of insulating material glued to the rail (2); and a housing (320) fixed to the support. Guiding system (1) according to claims 6 and 7, characterized in that said first and second attitude sensors (31,32) each comprise a housing (320) forming a Faraday cage and housing an accelerometer of a sensor respective attitude. Guiding system (1) according to claim 8, wherein the support (310) has two faces conforming to the shape of respective faces of the lower element (22) and the connecting element (23). A guidance system (1) according to any one of claims 5 to 9, wherein each of said first and second attitude sensors (31, 32) comprises: an accelerometer (341) configured to measure an acceleration component along said axis; a calculation circuit (342) configured to calculate the attitude of the attitude sensor (31, 32) as a function of the measurement of the accelerometer (341). The guidance system (1) of claim 10, wherein said respective accelerometer of the first and second attitude sensors (31,32) is an accelerometer with 3 non-collinear measuring axes. A guidance system (1) according to any one of claims 5 to 11, wherein said first and second attitude sensors (31,32) are glued to the connecting element (23) and the lower element ( 22). Guiding system (1) according to any one of claims 5 to 12, wherein said first and second attitude sensors (31,32) are spaced apart by a distance of at most 5 meters along the rail axis (2). A guidance system (1) according to any of claims 5 to 13, further comprising a wire connection (40) between the first and second attitude sensors (31,32), said wire connection being attached to the element lower (22) of the rail (2) via a staple. A guidance system (1) according to any one of claims 5 to 14, wherein a gap (240) is provided in the lateral recess (24) between an upper face of the attitude sensors (31,32) and the upper element (21).

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